When people ask whether or not they believe ghosts or aliens exist, they typically point to something that is somewhat tangible as proof such as “the government says it is real” or “this video explains it all”. I think these responses are valid, but with low confidence in what they’re trying to prove. A government can simply be making stuff up and a video explaining it could of simply been misinformed into some false truth.
On the contrary, I think they exist because of statistical improbability. I see that there are an uncountable amount of videos claiming to have recorded proof for ghosts and aliens. Assuming that 99% of them are hoaxes, clout chasers, or misidentified phenomena, that still leaves 1% of all those videos to be true. As long as the percentage is not 100%, it means that there is solid proof out there, weak in confidence or not, it’s a lead to the truth.
I will also point out that the first recorded sighting of aliens that I can find is from 1947, and the Loch Ness Monster was “first brought to world-wide attention” in 1933, so your claim of historical evidence falls apart.
In fact, isn’t it perhaps suspicious that sightings of alien spacecraft didn’t start happening until semi-modern technology existed? Why aren’t there cave paintings from neanderthals of flying saucers? Why isn’t there evidence from ancient Egypt or Rome? It’s almost as though modern science fiction bringing such things to mind was the catalyst for these sightings.
Thing about Nessy is that it is localized. It started in an area in Scotland. Assuming Nessy was a worldwide phenomenon where sightings are found more than a couple of times a month, it’d be different. How small the location of sightings and frequency of sightings play an massive role in the probability of their existence.
To rebut your documentation claims, there is evidence to suggest that sighting have been documented prior to 1947, but only formally reported on 1947. However, these claims may of had religious bias so they cannot be used individually as evidence towards statistical proof. It is its decentralized nature of documentation that makes it moreso valuable. These documentation are indeed from ancient Egypt and Greece, so your argument for their origin falls short there.
Nessy is purported to be a single creature living in a single Loch in Scotland; why would there be sightings elsewhere in the world? That’s like saying “The Eiffel Tower is only ever sighted in Paris, isn’t that suspicious?”
Given the relatively small number of visitors to Loch Ness vs. the number of people in the world with cameras who could presumably document aliens or ghosts, I’d argue that the sightings per visitor are at a significantly higher rate than UFO or ghost sightings.